But now there is an offshoot of Openwrt called Gargoyle (http://www.gargoyle-router.com/). Like Openwrt, they both can run in a virtual machine! So you could run several routers all on one system. That is something so far you can not do on a commercial plastic router. Hopefully, I will be doing an install set up soon. If you can do the openwrt install, then the gargoyle install should be easy.
If you go to their download page, you can easily choose the right firmware to download for an X86 system. Linux users will want to have the software dd available to transfer the image to a drive. You do get a gui interface to interact with remotely like most routing software, That way you are not locked into the command line.
Gargoyle is only about 17 megabytes, so choice of media storage such as a compact flash drive very accessible. Never tested this software, but it begs to be tested!